Subshrub, glabrous in all parts except flowers, pale green. Leaves ± linear, simple, entire, thick-textured, scarcely petiolate. Verticillasters 4-10-flowered, all remote. Calyx tubular-infundibuliform, coriaceous, indistinctly nerved, scarcely bilabiate, with 7-10 spiny spreading teeth, not or scarcely expanding in fruit. Corolla bilabiate; tube shortly exserted from calyx tube, V-annulate within; upper lip horizontal, densely pilose-villous, entire; lower lip 3-lobed with median lobe larger than laterals. Stamens 4; filaments and thecae glabrous; thecae bilocular, diverging. Style with 2 short equal lobes. Nutlets not known; in juvenile stage apparently truncate.